System for cooling by evaporation for combustion engines



April 29, 1941. A. BERGER ETAL 2,240,065

SYSTEM FOR coonme BY EVAPORATIQN FOR COMBUSTION ummss Filed Dec. 8, 1939Ar+hur Brgg Reinhcfld Freu ag INVENTORS Patented Apr-.29, 1941 UNITEDSTATES PATENT OFFICE SYSTEM Fon COOLING BY EVAPORATION ron COMBUSTIONENGINES Arthur Berger, -Stuttgart-berturkheim, andStuttgart-Unterturkheim, Germany, assignors to Daimler-BenzAktiengesellschait, Stuttgart Unterturkheim, Ger- Reinhold Freitag,

many

Application December 8, 1939, Serial No. 308,232 In Germany November 28,1938 6 Claims.

The present invention relates to a system for cooling combustionengines, and more particu larly aircraft engines, by evaporation of acooling liquid.

One object of the invention is to produce a cooling system of this typein which the vaporizer chamber and the recirculating pump are combinedinto a single constructional unit of small dimensions. a g

A further object of the invention is to provide a cooling system of thetype described, in which the condensate is returned to the vaporizerchamber and a single pump located directly below and communicating withthe vaporizer chamber serves to recirculate both the liquid separatedduring evaporation and the condensate.

Still another object is to produce a cooling system which operatesefllciently and reliably and without any appreciable loss of coolingliquid.

These and other objects are accomplished by the arrangement andcombination of elements set forth in the following detailed description,defined in the accompanying claims and illustratively exemplified in theaccompanying drawing, in which:

Fig. 1 is a substantially diagrammatic illustration of a cooling systemaccording to the invention appliedto an aircraft engine.

Fig. 2 is a vertical section through the vaporiz-- er housing andrecirculating pump. and

Fig. 3 is a horizontal section taken on line 3- of Fig. 2.

Figs. 2 and 3 are on a larger scale than Fig. 1.

In the figures, a denotes the vaporizer housing, the upper portion 01'which constitutes the vaporizer chamber proper b is a'hlgh pressure ductconnecting the vaporizer chamber with the cooling spaces 0 of the engined. 'Superheated water or other cooling liquid passes from the coolingspaces 0 through the high pressure duct b. to the vaporizerchamber inthe housing a. The

housing a with the cooling spaces c of the engine d. The steam formed inthe vaporizer chamber is led through a duct f to-a condenser g, whichmay be disposed in the tip of a wing h. A duct i returns the condensateback to the vaporizer chamber.

The pressure duct 1) communicates with the vaporizer chamber in thehousing a by means of entrance ports k. The ports I: are closed on theinside or the vaporizer chamber by spring duct e connectsthe lower partof the vaporizer flaps l which open more or lessin response to thepressure prevailing in the high pressure duct b. In addition, the flapsl influence the direction of the liquid jets emerging from the ports 7::into the vaporizer chamber a. Thus, the ports is are self-adjusting andresponsive to the pressure prevailing in the cooling system.

A pressure pump m'is arranged in the bottom.

portion of the vaporizer housing a. The pump m is driven from the engined through gearing n, and its pressure side is connected to the coolingspaces c of the engine by means of the duct e. A one-way valve 0 isprovided in the duct e in order to prevent back-flow of the coolingliquid from th; cooilng spaces c to the pump m.

The device operates as follows: The cooling liquid in the cooling spaces0 of the engine d is superheated to a temperature exceeding its va-.

porlzing temperature, but, in the cooling spaces and in the highpressure duct b,'the super-heated liquidis maintained under a pressurepreventing its evaporation. In accordance with the pressure prevailingin the pressure duct b, the spring flaps l uncover the entrance ports itinto the vaporizer chamber to a greater or less degree, and jets ofsuperheated liquid are discharged into the vaporizer chamber which isapproximately under atmospheric pressure.

Owing to the sudden reduction of pressure, the superheated coolingliquid entering the vaporizer chamber separates into vapor. and liquid.The

vapor flows through the duct 1 to. the condenser y. The condensate isreturned to the vaporizer chamber a through the duct 1 by means of asecond pump 21. The liquid separated from the vapor in the upper portionof the vaporizer chamber and the condensate returned to said chamber,both are collected at the bottom of the vaporizer housing a and enterthe pump m at the suction side thereof. From the pump m, the entireliquid is recirculated under a pressure of about iatmospheres throughthe one-way valve 0 into the duct 1 and from there to the cooling spaces0 of' the engine d.

Instead of providing a second pump 11, the condensate may be returned tothe vaporizer a by its own gravity, or the pump m may be con structed asa double-acting pump, the suction side of which serves to suck thecondensate from the. condenser 9 back into the vaporizer chamber. Incombustion engines with several rows of cylinders, the ducts connectingthe vaporizer housing a and the pump 11: with the cooling spaces c maybe arranged symmetrically in such a manner that corresponding ducts haveequal lengths.

We claim: I

1. A system for cooling a combustion engine by evaporation, comprising avaporizer chamber, a,

' pressure duct to feed superheated cooling liquid to. said chamberwhere it is separated into vapor and liquid, a condenser, a vapor ductconnecting said chamber with said condenser, a condensate duct returningthe condensate from the condenser to said vaporizer chamber, ,and a,liquid pump disposed immediately below said vaporizer chamber and indirect communication therewith to collect and recirculate both saidseparated liquid and said condensate.

2; A system for cooling a combustion engine by evaporation, comprising avaporizer housing and a liquid pump in the bottom portion of saidhousing, the latter having self-adjusting entrance ports responsive tothe pressure prevailing in the cooling spaces of the engine.

3. A system for cooling a combustion engine 'by evaporation, comprisinga vaporizer housing and a liquid pump in the bottom portion of -saidhousing, the latter being provided with entrance ports and having springflaps normally closing said entrance ports said spring flaps beingadapted to open in response to the pressureprevailing in recirculatingliquid pump in the bottom portion of said housing, a pressure duct fromsaid liquid pump through the cooling spaces of the engine.

back to said vaporizer housing, and a one-way valve in said pressureduct to prevent back-flow of cooling liquid from the cooling spaces ofthe 6. A system for cooling a combustion engine by evaporation,comprising a vaporizer housing, a liquid pump in the bottom portion ofsaid housing, acondenser disposed outside of said housing,

